title: Mouse lymphatic endothelial cell targeted probes: anti-LYVE-1 antibody-based magnetic nanoparticles.
abstract: OBJECTIVE
  To investigate the specific targeting property of lymphatic vessel endothelial hyaluronan receptor-1 binding polyethylene glycol-coated ultrasmall superparamagnetic iron oxide (LYVE-1-PEG-USPIO) nanoparticles to mouse lymphatic endothelial cells (MLECs).
  
  
  METHODS
  A ligand specific target to lymphatic vessels was selected by immunohistochemical staining on the sections of a Lewis subcutaneous transplanted tumor. The z-average hydrodynamic diameter (HD), zeta potential, and the relaxivity of PEG-USPIO and LYVE-1-PEG-USPIO nanoparticles were determined with a laser particle analyzer and magnetic resonance T2 spin echo sequence, respectively. Prussian blue staining and transmission electron microscopy (TEM) of nanoparticle labeled cells were performed to determine the nanoparticles' binding form. Magnetic resonance imaging (MRI) was performed in vitro to evaluate the signal enhancement on the T2 spin echo sequence of the nanoparticle labeled cells. The iron content of the labeled cells after the Prussian blue staining and MRI scanning was determined by atomic absorption spectroscopy (AAS).
  
  
  RESULTS
  The anti-LYVE-1 antibody was used as the specific ligand to synthesize the target probe to the MLECs. The mean z-average HDs of the LYVE-1-PEG-USPIO and PEG-USPIO nanoparticles were 57.42 ± 0.31 nm and 47.91 ± 0.73 nm, respectively, and the mean zeta potentials of the LYVE-1-PEG-USPIO and PEG-USPIO nanoparticles were 12.38 ± 4.87 mV and 2.57 ± 0.83 m V, respectively. The relaxivities of the LYVE-1-PEG-USPIO and PEG-USPIO nanoparticles were 185.48 mM(-1)s(-1) and 608.32 mM(-1)s(-1). Cells binding nanoparticles were visualized as blue granules in the Prussian blue staining. The TEM results of the labeled cells showed the specific localization of nanoparticles. The AAS results of labeled cells after the Prussian blue staining and MRI scanning showed that the LYVE-1-PEG-USPIO nanoparticles had good binding selectivity for MLECs. MRI results indicated that the PEG-USPIO and LYVE-1-PEG-USPIO nanoparticles could generate contrast on T2-weighted imaging, and the correlation between R2 and the iron content of the labeled cells was significantly positive.
  
  
  CONCLUSIONS
  This study demonstrated that LYVE-1-PEG-USPIO nanoparticles might potentially be used as an MRI contrast agent for targeting MLECs, and the magnetic properties of LYVE-1-PEG-USPIO nanoparticles were suitable for MRI.
authors.affiliation: Department of Radiology, The First Hospital of China Medical University, Shenyang, Liaoning, PR China.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Guo
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.forename: Ke
authors.initials: K
authors.lastname: Ren
authors.forename: WenGe
authors.initials: W
authors.lastname: Sun
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D005295:Ferrocyanides / Q000737:chemistry; D006023:Glycoproteins / Q000276:immunology* / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D026901:Membrane Transport Proteins; D051379:Mice; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D013054:Spectrophotometry, Atomic
chemical_list: D000911:Antibodies, Monoclonal; D005295:Ferrocyanides; D006023:Glycoproteins; D058185:Magnetite Nanoparticles; D026901:Membrane Transport Proteins; D011092:Polyethylene Glycols; C492273:LYVE1 protein, mouse; C000170:ferric ferrocyanide
keywords: lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1); magnetic resonance imaging (MRI); mouse lymphatic endothelial cells (MLECs); nanoparticles; ultrasmall superparamagnetic iron oxide (USPIO)